In general, there are mainly three types of vacuum cleaners: wet, dry, and wet and dry. Dry vacuum cleaners are cleaned by means of filters, which filter only dry media such as dust and cannot pick up wet media. Wet vacuum cleaners can pick up wet media such as detergents and water. In wet vacuum cleaners, a wet type medium is sprayed first, and then the wet type medium and the dirt contained in the wet type medium are sucked up to perform the cleaning operation. In the wet vacuum cleaner there is a device, for example a separation tank, for separating air from water that is sucked into the wet vacuum cleaner together with the air. The wet and dry vacuum cleaner combines the functions of a dry vacuum cleaner and a wet vacuum cleaner.
The wet and dry vacuum cleaner includes a body, and a recovery tank is arranged in the body. The recovery tank is used for containing sewage generated after the vacuum cleaner cleans the floor. When the wet and dry vacuum cleaner is not in use, the body is generally maintained vertically. When the wet or dry vacuum cleaner is being used for cleaning operations, the body is maintained in a tilted state. During this time, the recovery tank inside the body will also tilt with the body. Because the sensing probe of the water level detector is placed near the sidewall of the recovery tank and the sewage tilts along with the recovery tank, the sensing probe of the water level detector will contact with the sewage before the recovery tank is full of sewage, resulting in an erroneous full water level alarm. Therefore, there is a problem in that e water level alarm is not accurate enough and results in false positives.